Biomedical subjects

Samira Guccione

Publications and source records attributed to Samira Guccione.

4 recordsLinked to original sources

PubMed2003

Functional genomics guided with MR imaging: mouse tumor model study.

To gain a better understanding of gene expression patterns in tumors, the authors used contrast material-enhanced magnetic resonance (MR) imaging to noninvasively characterize regions within the same tumor to provide a correlate for genomic analysis. Gene expression profiles of samples from a mouse tumor model obtained from contrast-enhanced and nonenhanced regions within the same tumor were compared with MR imaging and functional genomics. From these samples, 11000 genes were analyzed: 10 genes were up-regulated in the contrast-enhanced areas, and one gene was up-regulated in the nonenhanced regions. Several of these genes encode extracellular matrix proteins. Findings in this study demonstrate that MR imaging can serve as a powerful noninvasive tool for characterizing different regions of tumors to guide genomic analysis with high spatial and temporal resolution.

Animals↗

PubMed2003

Apparent diffusion coefficient: a quantitative parameter for in vivo tumor characterization.

PURPOSE: The purpose of the this study was to evaluate the potential of diffusion weighted imaging (DWI) to distinguish different tissue compartments in early, intermediate and advanced tumor stages. MATERIALS AND METHODS: Twenty-two male mice were induced with squamous cell tumor (SCCVII) and scanned with a clinical 1.5 T scanner. T1-SE, T2-FSE, diffusion weighted Line-Scan-MRI and contrast enhanced T1-SE were obtained from mice with early (tumor volume 10-100 mm(3)), intermediate (200-600 mm(3)), advanced tumors (600-1000 mm(3)) and tumor necrosis (>1500 mm(3)). The apparent diffusion coefficient (ADC) of different tumor compartments was calculated offline with a pixel-by-pixel method. The animals were sacrificed immediately after scanning and histopathologic correlation was performed. RESULTS: In early stages of tumor development, tumors appeared homogeneous on diffusion weighted images with an ADC of 0.64+/-0.06 x 10(-3) mm(2)/s. With tumor progression the ADC in the rim areas of tumor increased significantly (intermediate stage: 0.70+/-0.11 x 10(-3) mm(2)/s; advanced stage: 0.88+/-0.11 x 10(-3) mm(2)/s; tumor necrosis 1.03+/-0.06 x 10(-3) mm(2)/s), whereas the ADC in viable tumor remained constant. Histologically the areas with an increased ADC correlated well with areas of necrosis (reduced cell density). CONCLUSION: The ADC is a non-invasive technique to monitor changes in the biological structure of tumor tissue during tumor progression. Thus, DWI is a potential diagnostic tool for in-vivo tissue characterization.

Animals↗

PubMed2002

Tumor regression by targeted gene delivery to the neovasculature.

Efforts to influence the biology of blood vessels by gene delivery have been hampered by a lack of targeting vectors specific for endothelial cells in diseased tissues. Here we show that a cationic nanoparticle (NP) coupled to an integrin alphavbeta3-targeting ligand can deliver genes selectively to angiogenic blood vessels in tumor-bearing mice. The therapeutic efficacy of this approach was tested by generating NPs conjugated to a mutant Raf gene, ATPmu-Raf, which blocks endothelial signaling and angiogenesis in response to multiple growth factors. Systemic injection of the NP into mice resulted in apoptosis of the tumor-associated endothelium, ultimately leading to tumor cell apoptosis and sustained regression of established primary and metastatic tumors.

Adenosine Triphosphate↗

PubMed2002

Combined vascular targeted imaging and therapy: a paradigm for personalized treatment.

In order to be successful in personalizing treatment, methods for selecting patients as well as good surrogate biomarkers for monitoring the effects of treatment are required in addition to development of an efficacious targeted therapy. We have developed a polymerized nanoparticle platform technology that will allow us to put different targeting moieties on the surface of the particles in addition to loading the particles with different contrast and therapeutic agents. We have proven that these nanoparticles can be targeted to endothelial receptors and different payloads of contrast and therapeutic agents have been delivered to target cells with high target to background ratios. Using this combined vascular targeted imaging and therapy approach, we are optimistic that personalized treatment regimens can be developed for different disease processes such as cancer, inflammation, and ischemia.

Animals↗